expand-stroke.py

from fontParts.fontshell.font import RFont
from fontTools.pens.cocoaPen import CocoaPen

f = RFont("expand-stroke.ufo") # a ufo with one line path for a glyph (no closed contours)

canvasSize = 800
numFrames = 200

def getGlyphPath(glyph):
    pen = CocoaPen(glyph.font)
    glyph.draw(pen)
    b = BezierPath()
    b.setNSBezierPath(pen.path)
    return b

def drawMyPath(b, frame, sx, sy, lines):
    translate(150, 165)
    a = (frame/numFrames)*360 #angle
    with savedState():
        for i in reversed(range(lines)):
            c = i%2
            fill(c, c, c, 1)
            strokeWidth(i/10+1)
            b2 = b.copy()
            b2.rotate(a, (0, 0))
            b2.scale(sx, sy, (0, 0))
            stroked = b2.expandStroke((i + 3)*3) # this is the new expand stroke method
            stroked.scale(1/sx, 1/sy, (0, 0))
            stroked.rotate(-a, (0, 0))
            drawPath(stroked)

def sineLoop(time, totalFrames):
    return (sin(((time-totalFrames/4)/totalFrames*2)*pi)+1)/2

b = getGlyphPath(f["z"])

for frame in range(numFrames):
    newPage(canvasSize, canvasSize)
    frameDuration(1/25)
    sx = sineLoop(frame, numFrames)*3+0.1
    sy = sineLoop(frame+(numFrames/2), numFrames)*6+0.1
    rect(0,0,canvasSize,canvasSize )
    drawMyPath(b, frame, sx, sy, 4)
 
saveImage('test.gif')